feat(runtime): add AbortController and AbortSignal - #447
Merged
Conversation
Install the DOM abort primitives as globals in every isolate, modeled on Node's internal/abort_controller.js: AbortController, and AbortSignal with the abort/timeout/any statics, onabort with HTML event-handler semantics, and WebIDL-shaped interfaces (enumerable members, Symbol.toStringTag, brand-checked accessors). The builtin (internal/abort-signal.js) runs from Events::Init right after the Event/EventTarget builtin it is layered on. Deviations from Node, documented in docs/abort-signal.md: no DOMException (default reasons are Error instances with name patched to AbortError/TimeoutError, the same stand-in performance.js and structured-clone.js use) and no WeakRef bookkeeping (a timeout() timer holds its signal until it fires; any() links source -> dependent strongly and unlinks as soon as either side aborts). Adds RangeError and NumberIsInteger to primordials and the eslint restriction lists, and a 20-spec Jasmine suite.
|
No actionable comments were generated in the recent review. 🎉 ℹ️ Recent review info⚙️ Run configurationConfiguration used: Repository UI Review profile: CHILL Plan: Pro Plus Run ID: 📒 Files selected for processing (10)
Included review availability: Your plan provides up to 2 included reviews per hour; 0 remain after this review. 📝 WalkthroughWalkthroughThe runtime adds global ChangesAbortSignal runtime support
Estimated code review effort: 4 (Complex) | ~45 minutes Merge Risk: ⚪ Minimal · up to The PR adds AbortController and AbortSignal support with targeted tests and documentation; no actionable merge-blocking risk remains, so it is merge-ready after normal checks and review. Sequence Diagram(s)sequenceDiagram
participant EventsInit
participant BuiltinLoader
participant AbortSignalBuiltin
participant GlobalThis
EventsInit->>BuiltinLoader: RunBuiltin(kAbortSignal)
BuiltinLoader->>AbortSignalBuiltin: load internal/abort-signal.js
AbortSignalBuiltin->>GlobalThis: expose AbortController and AbortSignal
Suggested reviewers: Poem
🚥 Pre-merge checks | ✅ 5✅ Passed checks (5 passed)
✨ Finishing Touches📝 Generate docstrings
Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out. Comment |
Match Node's memory behavior: internal references never keep an unobservable signal alive and never drop an observable abort. - timeout() timers close over a WeakRef; a FinalizationRegistry cancels the pending native timer when the signal is collected. - any() links are WeakRefs in both directions with prune registries, so per-request composites never accumulate on a long-lived source and a composite whose sources all died stops being retained. - A gcPersistentSignals set strong-holds exactly the signals whose abort someone can still observe: live timeout signals and non-empty composites while they have abort listeners, plus timeout sources a composite follows until their timer fires. The listener accounting comes from a new symbol-keyed listener-mutation hook in events.js, called from every listener-list mutation path (add, remove, once-splice during dispatch) and handed to the abort builtin in a one-shot through its binding, so it cannot be bypassed via a captured EventTarget.prototype.addEventListener. Adds WeakRef/FinalizationRegistry captures to primordials and the eslint restriction lists, and 8 GC specs driven by __collect() plus a finalization-registry substrate canary.
…ilities
Add a sixth fixed wrapper parameter, `internals`: one plain per-isolate
object (stored via Caches::StateFor) handed identically to every builtin
and reachable from nowhere else. Producers publish during their init,
consumers read during theirs, so the Runtime::Init ordering is the
dependency graph and a missing key fails loudly at init.
Both existing ad-hoc channels migrate onto it: events.js publishes the
kListenerChanged hook key (read by abort-signal.js, previously a one-shot
relayed through the abort builtin's binding) and setListenerErrorReporter
(called by error-events.js, previously the _installListenerErrorReporter
one-shot on the app-reachable global target). No capability ever sits on
an app-reachable object anymore, even transiently.
Documented in the js README as an interim mechanism: if cross-builtin
needs outgrow one shared object, migrate to a Node-style private
internal-module tier (require("internal/...") resolved for builtins
only) and fold internals into it.
NathanWalker
approved these changes
Aug 24, 2026
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
What
Installs the DOM Standard's abort primitives as globals in every isolate (main and workers), modeled on Node's
internal/abort_controller.js:AbortController—controller.signal(stable identity) andcontroller.abort(reason?).AbortSignalextending the runtime'sEventTarget, withaborted,reason,throwIfAborted(), theabortevent, andonabortwith HTML event-handler semantics.new AbortSignal()throwsTypeError: Illegal constructor.AbortSignal.abort(reason?),AbortSignal.timeout(delay)(Node's delay validation), andAbortSignal.any(signals)(composite flattening, first-aborted-reason-wins, spec-ordered state flips before events fire).Symbol.toStringTag, brand-checked accessors (via private fields).How
The builtin (
NativeScript/runtime/js/abort-signal.js) runs fromEvents::Initimmediately after theEvent/EventTargetbuiltin it is layered on.This PR also introduces a sixth fixed wrapper parameter,
internals: one plain per-isolate object (aCaches::StateForslot) handed identically to every builtin and reachable from nowhere app code can see — the private channel for cross-builtin capabilities. Both previously ad-hoc channels now ride it: thekListenerChangedhook key (events → abort-signal) andsetListenerErrorReporter(error-events → events), replacing the_installListenerErrorReporterone-shot that transiently sat on the app-reachable global target. Documented in the js README as an interim mechanism, with the intended end-state being a Node-style private internal-module tier (require("internal/…")for builtins only).RangeError,NumberIsInteger,WeakRef, andFinalizationRegistryare added to primordials (and the eslint restriction lists).GC contract (Node-equivalent, documented in
docs/abort-signal.md)Internal references never keep an unobservable signal alive and never drop an observable abort:
timeout()timers close over aWeakRef; aFinalizationRegistrycancels the pending native timer if the signal is collected first.any()links areWeakRefs in both directions with prune registries, so per-request composites never accumulate on a long-lived source, and a composite whose sources all died stops being retained.gcPersistentSignalsset strong-holds exactly the signals whose abort someone can still observe: live timeout signals and non-empty composites while they have abort listeners, plus timeout sources a composite follows until their timer fires. The listener accounting comes from a new symbol-keyed listener-mutation hook inevents.js(called from add, remove, and theonce-splice during dispatch), published on the builtin-onlyinternalschannel — so it cannot be bypassed via a capturedEventTarget.prototype.addEventListener.Deviation from Node
No
DOMExceptionin this runtime: default reasons areErrorinstances withnamepatched to"AbortError"/"TimeoutError", the same stand-inperformance.jsandstructured-clone.jsuse.Tests
null), throwing listeners not stopping dispatch,oncelisteners,onabortset/replace/clear, delay validation,any()flattening/dedup/no-double-fire, arbitrary iterables, toStringTag, brand checks.__collect(): a finalization-registry substrate canary, collectability of unobserved timeout signals and composites, survival (and delivery) for listened ones, a composite keeping a dropped timeout source alive until it fires, release of a listened composite once its last source dies, and release on last-listener removal.Full iOS suite passes with 0 failures.